Pancreatic ductal adenocarcinoma (PDA), which has an overall five-year survival rate of 6%, is predicted to become the second leading cause of cancer-related death in the US. 80% of PDA patients who have surgery will suffer a recurrence likely due to undetectable metastases present at diagnosis; yet standard of care radiographic imaging and blood-tests can be imprecise and are not predictive of metastatic burden. Circulating tumor cells (CTCs) are thought to mediate much of the metastatic process, and while FDA-approved tests are established for enumeration of CTCs shed into the blood by breast, prostate, and colorectal tumors, such tests lack sufficient sensitivity for pancreatic tumors. Recently, we showed that: PDA CTC heterogeneity promoted a more aggressive phenotype; CTC clusters were associated with higher metastatic potential; and seeding at distal sites required more than one clone during the course of metastatic disease progression. This proposal seeks to develop and optimize a liquid biopsy for the measurement of single and clustered CTCs and their molecular signatures, in order to address the urgent unmet need for non-invasive clinical monitoring of PDA patient metastatic burden, disease progression, and treatment response. This industry/academic partnership will bring together Becton Dickinson (BD)'s strengths in rare cell capture and molecular analysis, Johns Hopkins' PDA antigen discovery programs, and Penn's pre-clinical PDA models, robust clinical PDA programs, and dedicated Circulating Tumor Material Laboratory. First, technologies for efficient enrichment and sorting of CTC clusters with high purity, recovery and viability will be optimized so that high quality RNA can be isolated for downstream molecular analyses (RNA-seq). The BD Focus, which is a rare cell enrichment platform being developed at BD, will be used for pre-enrichment and sorting using a combination of cell surface antibody and RNA-based probes (i.e., BD's unique ?nanoflare? technology). Second, a panel of candidate CTC biomarkers will be finalized and validated in PDA pre-clinical mouse models as well as patients with metastatic PDA. Finally, we will establish proof of concept for the CTC biomarkers to predict and monitor the metastatic burden of a cohort of PDA patients starting at diagnosis and continuing after commencement of therapy, and at time points coinciding with monitoring CT scans. Single cell and clustered CTC counts and molecular signature will be correlated with metastatic burden, and survival. The ability to enrich and perform molecular characterization of CTC single cells and clusters will provide a novel and crucial technology to detect and monitor metastasis in PDA patients so that the appropriate therapeutic strategies can be utilized in order to increase overall survival rates.